From picking a job to selecting a spouse, we face many decisions that will affect our lives far into the future. Those choices rest on some assumptions, notes Daniel Gilbert, a psychologist at Harvard University. "Any kind of lifetime commitment is based on your belief that you know the person you're going to be in 10 years."
To investigate people's predictions about their future selves, Gilbert teamed up with Harvard postdoctoral fellow Jordi Quoidbach and Timothy Wilson, a psychologist at the University of Virginia in Charlottesville. The trio devised a series of online experiments in which a total of more than 19,000 people participated. In one, adults between ages 18 and 68 filled out a questionnaire, scoring themselves on basic personality traits such as extraversion, emotional stability, and openness to new experiences.
Then the researchers asked them to do it all again, this time answering either as they would have 10 years ago, or as they thought they would 10 years in the future. The surveys from participants of all ages indicated that on average people felt they had changed more in the past decade than they would in the next, the researchers report online today in Science.
Although teenagers are notoriously bad at envisioning their future selves ("Of course I'll always want this butterfly tattoo!"), Gilbert says he was surprised that even older people seem to underestimate how much they'll change. For example, 68-year-olds reported modest personality changes in the previous decade, but 58-year-olds predicted very little, if any, change in the coming decade, even though their survey answers indicated that they had changed considerably since they were 48. Several follow-up experiments suggested that these differences reflect errors in predicting the future rather than errors in remembering the past. Gilbert and colleagues call this effect "the end of history illusion," because it suggests that people believe, consciously or not, that the present marks the point at which they've finally stopped changing.
In additional surveys, the researchers found that people similarly underestimate changes in their personal values (things like success and security) and preferences (like their favorite band and best friend). "What these data suggest, and what scads of other data from our lab and others suggest, is that people really aren't very good at knowing who they're going to be and hence what they're going to want a decade from now," Gilbert says.
A final experiment hints at how this bias might affect financial decisions. Gilbert and colleagues asked some participants how much they'd pay in 2012 to see their current favorite band play a concert in 2022. They asked others how much they'd pay to see their favorite band from 2002 play a concert "next week" in 2012. People were willing to pay 61% more, on average, for the future concert with their current favorite band than people 10 years older than them were willing to pay to see their favorite band from 2002 play in 2012. "You'd think by the time people reach middle age they'd realize that their favorite band today isn't necessarily going to be their favorite band in 10 years," Gilbert says. Instead, he and his colleagues write, "participants substantially overpaid for a future opportunity to indulge a current preference."
"The really interesting thing about this paper's finding is that it reveals how [a] common intuition is precisely wrong," says Nicholas Epley, a psychologist at the University of Chicago in Illinois. Epley says that he's reminded of a quotation from the 17th century French writer, François de La Rochefoucauld: "Everyone complains of his memory, and no one complains of his judgment."
"They really demonstrate two things, that people believe they have changed more than they will change, and that that belief is a mistake," says Leaf Van Boven, a social psychologist at the University of Colorado, Boulder. "What's fascinating about that is that people don't have this belief about other people or about the world," Van Boven adds. "We fully expect other people to change. We fully realize that we have changed in the past. There's something odd about this projection of the self into the future that's psychologically unique."
But not everyone is sold on the study's conclusion that people underestimate how much they will change. Another possibility is that people "might well anticipate substantial change, yet not know how they would change, and thus, just predict the status quo," says Shane Frederick, who studies decision-making at Yale University. Frederick did a similar, but much smaller study as part of his Ph.D. thesis and published it in a book chapter in 2003. He also found that people predicted less change in the future than they'd experienced in the past. But instead of being fooled by an illusion, people might just have a rational reluctance to predict the unknowable, says Frederick, who cites a famous quotation from the great 20th century mathematician John von Neumann: "There's no sense in being precise when you don't even know what you're talking about."
We can never completely predict the future, but that doesn't mean we can't anticipate it and make better decisions, Gilbert says. "The single best way to make predictions about what you're going to want in the future isn't to imagine yourself in the future, ... it's to look at other people who are in the very future you're imagining," he says. For example, he and colleagues previously reported that people make more accurate predictions about how they'll react to a future event when they know how other people have reacted previously to it. "Other people provide some of the best information we can get about the future."